Switching device comprising primary and secondary crossbar switches



y 1954 A. K. DIESEN 2,683,773

SWITCHING DEVICE COMPRISING PRIMARY AND SECONDARY CROSSBAR SWITCHES Filed May 10, 1950 4 Sheets-Sheet 1 as: e32 830 I f I m1 M12 M13 M14 9 12L 0 enter July 13, 1954' IESEN 2,633,773

A. K. D SWITCHING DEVICE COMPRISING PRIMARY AND SECONDARY CROSSBAR SWITCHES Filed May 10, 1950 4 Sheets-Sheet 2 A. K. SWITCHING DEVICE COMPRISING PRIMARY July '13, 1954 DlESEN 2,583,773

AND SECONDARY CROSSBAR SWITCHES I Filed May 10 1950 4 Sheets-Sheet 3 la-c/ R1 R2 R3 R4 R5 R6 R7 R8 R9 July 13, 1954 A. K. DIESEN 2,683,773

SWITCHING DEVICE COMPRISING PRIMARY AND SECONDARY CROSSBAR SWITCHES Filed May 10, 1950 4 Sheets-Sheet 4 r7 l 1 471 k l// L h "-20; f 2-73 414 l I 249 R20 R28 R29 R47 Patented July 13, 1954 NlTED STATEfi SWITCHING DEVICE COMPRISING PRIMARY AND SECONDARY CROSSBAR SWITCHES Anton Kristian Diesen, Stockholm, Sweden, as-

signor to Teiefonaktiebolaget L M Ericsson,

ENT OFFICE Stockholm, Sweden, a company of Sweden Application May 10, 1950, Serial No. 161,144

Claims priority, application Sweden May 20, 1949 2 Claims.

marker can receive signals from the register indicating from which one of the selecting units A-C the call is coming and to which one of the selecting units D-F the call is directed. The marker connects both said selecting units to the marker, and since there are direct links between each one of the selecting units A-C and each one of the selecting units D-F, the marker can set a connection between the calling line L and a each connecting path there are test circuits, called line T simultaneously with other markers wl'iich indicate if the connecting path is free and setting connections between other selecting units. with help of which a marker can select and set Fig. 1 shows a selecting unit consisting of crossa connection between a calling line connected to bar switches KIK4 for incoming lines and the one selecting unit and a called line or a line corresponding to A, B or C in Fig. 5. Connecting within a called group of lines connected to the relays MIZ-MM for three markers are comother selecting unit. It is in this connection prised in Fig. 1. In Fig. 3, L is an incoming line desirable that the marker can test all possible and LR a relay set for the same line. The line combinations of connecting paths through the L is over the wires a-d connected to the contwo selecting units. The object of the invention tacts in the cross-bar switch Kl in Fig. 1 correis to achieve this in a simple manner. spending to the selecting magnet SH. When a The invention is characterized by a relay decall comes in over line L the relay set LR is vice in the marker, which successively operates connected to a register REG over a registerconnecting relays connecting together test wires finder RS. Signals thereafter come in over line for connecting paths through said first select- L and set the register REG so, that the called ing unit with test wires for connecting paths 2; line or group of lines is marked. Suppose now through said second selecting unit, whereby each that a group of lines TIT4 in Fig. 2 are called connecting relay only connects one test wire for and a free line within said group is to be selectconnecting paths through said first selecting ed and connected with line L. The register REG unit at a time from each secondary cross bar is connected to a marker over a selector MS. switch in this selecting unit. Said relay device 50 The m r aOCOIdiIIg to Figs- Comprises a is thereby controlled by a test device, which inregistering device MR, which is set from the terrupts the successive connection, when a group ster EG an po t 01115 t called group of of connecting paths is connected that contains lines, and the selecting unit'D. E F in 5 at least one connecting path, over which the comprising the called group of lines and shown communication can be set. 55 in Fig. 2. One of the relays R!fiR|2, each of The invention will be described more closely which pertains to a. selecting unit for outgoing with reference to the accompanying drawings lines, is thereby operated. In the present case Figs. 1-5. relay R! 2 is operated, which relay pertains to Figs. 1-2 show selecting units with primary the selecting unit shown in Fig. 2. The conand secondary cross-bar switches. tacts 22l222 are closed. One of the relays Figs. 3-4 show a marker. R'IR9 is simultaneously operated from the reg- Fig. 5 is a general diagram. ister REG over one of the contact rows al-a3.

On the general diagram according to Fig. 5, Each of the relays pertains to a selecting unit for A, B and C are selecting units comprising primary incoming lines. In this case relay R9 is operated, and secondary cross-bar switches, to which inwhich pertains to the selecting unit shown in coming lines L are connected, whilst D, E and F Fig. 1 and to which the calling line L is connectare selecting units, to which outgoing lines T ed. The contacts Nil-I95 are closed. The folare connected. The incoming lines can be conlowing circuit is closed if the two selecting units nected over register finders RS to registers REG, in Figs. 1-2 are free: contacts H and 15, which are set by signals from the connected line Winding on relay MI2, rectifier El, wire 9', conso that an outgoing line 'I or a group of outgotacts I95 and 22!, wire 1, rectifier E2, winding on ing lines is marked. After a register REG has relay M22, contacts 25 and 2! to negative. Relays been set, it connects itself over a selector MS to Ml2 and M22 attract their a'rmatures. Contacts a marker M. Each selecting unit A-C has its I 320 and 233ll are operated. The circuit is own group of registers REG, and therefore the switched by contacts I and 24 to relays MI! and M21, which operate. Contacts I l--|2 and 21-22 are operated. The selecting units in Fig. l and Fig. 2 are thereafter marked busy and other markers corresponding to the relays M|3M|4 and M23-M24 cannot be connected. The following circuit is closed: contacts i2 and 16, wire ,1, winding on relay R6, wire 8, contacts and 22, to negative. Relay RE attracts its armature. The contacts I 6!l 64 are closed. The following circuits are closed:

(1) The selecting magnet SH in Fig. l is energized over contact H52, contact row bl in MS, register REG, RS and LR and wire d. Contac H6 is closed. Relay Kll operates. Contacts llE-l !9 are closed.

(2) Relays V3 and V4 in Fig. 2 are operated over contact I63, contacts in MR and wire as among the indicating wires x-z. Contacts $38S and 13-16 are closed and indicate which one of lines Tl--T4 pertains to the called group of lines.

(3) Relay RM is operated over contact 55 wire to, contacts 2fi3293. The contacts l-H-AHQ are closed, the test relays R2il-R2$l thereby being connected over the wires h-7c and contacts i3--2l to the test wires for the connecting paths which can reach line L through the selecting unit in Fig. l.

(4) Relay R is simultaneously operated. over wire 20 and contacts 3fl3-393. The contacts ti t-5&5 are operated.

(5) Relay R2 is also operated over contact 56 3 in the following circuit: contacts [55, i526, i222, 33, 43, 152, rectifier E3, contacts i5 5, E i-6 and Hit, winding on relay R2 to negative.

The following circuit is closed: contacts ltl, 2'22, I2 and till, wire it, winding on relay Vi to negative. Relay Vi attracts its armature. Contacts 3335 are operated. Simultaneously, relay R3 receives current over contact 23. Relay RS operates and relay R2 is held. Contacts i3li39 are operated. The following circuit is closed: contact 35 in Fig. 1, wire q, contacts [3i and 21, winding on relay RI, wire 1', contact di to negative. Relay R! operates. Contacts see and 528 are actuated. Relay R2 releases its armature whilst relay R3. is held in the following circuit: contacts ifi l, 169, 56, Hit and H25, winding on relay R3 to negative. When relay R2 released its armature, relay Vi released its armature and relay V 2 was operated in a circuit over contacts I25 and lZ-il. Contacts d3d5 in Fig. l are closed. When contact 12! opens, relay R: releases its armature. Relay now receives current over contacts x2e, H2 and i3 3 and attracts its armature simultaneously with relay R3 being held. Contacts lii49 are operated. Relay RI is operated again, this time in a circuit over contact 45, wire q, contacts its, i i! and 32. Relay R3 releases its armature when contact I2!) is operated and relay R4 is held over contacts we, i and M5. In this way relays V|V2 are operated one after the other until all relays in the relay chain R2--R5 have been operated or relay R ii in Fig. 4 releases its armature, which takes place when a free connection between line L and one of the lines Ti-T i is found, whereby one of the relays R2tR22i attracts its armature.

In the relay chain R2R5 each selecting unit for outgoing lines D-F in Fig. 5 has a row of contacts i25| i7, 621-448 or l29l l9. The wires coming from said contact rows can be connected to relays, V|V2, in any of the selecting tacts, for example Nil-I94 on relays Rl-R9. If the relay chain is passed without any free connection being found, relay R5 is actuated and a circuit is closed to an alarm device AL. Relay R5 is thereby held in a circuit over contact I53.

During the searching process, the following circuits are closed for the test relays R2GR29 when relay V! operates: contacts 99-90 in Fig. 2, circuits connected in parallel over contacts 9398, rectifiers e6el, contacts 84-, 1486 i6, 8i82, ll-42, selecting magnets S8|--S'll, contacts 5l--5G, selecting magnets S5l-S5S, contacts S t-33 in Fig. 1, 3242, selecting magnets S3l-S4I, contacts |09l0l, Nil-H0, i82il, wires h k, winding on relays R20R29, contacts 4Hi4i2, to negative. If all the connecting means are free, all the relays RZD-RZS operate. We suppose that at least relay R20 attracts its armature. The contacts 201-403 are operated. Relay R4! becomes currentless and releases its armature. All the test circuits are broken at contacts 4l24l4 and only the relay which is operated and lies first in the relay chain R2il--R29 is held. In the present case relay R20 is held over contact 202. The following circuit is closed: from the positive pole on an auxiliary battery V+, resistance H, contacts 3H and EM, wire h, contacts 26, H9 and lfll, selecting magnet SM, contacts 42 and 33, selecting magnet S59, the circuits connected in parallel over contacts 5l50, selecting magnets SSI-S'H, contacts 8l82ll'l2, l484--'I6-- 85, windings I and II on relays P20P2|, contacts 93-43, 98-99. The windings II on relays F P26P2l have such a hi h resistance, that none of the selecting magnets S50, SH or S8! can be connected in series with them. Relays P20-P2l form a relay chain, in which only one relay at a time can be operated. We suppose that relay P26 attracts its armature but not relay PM. Contacts 9il-9 i are operated. The following circuit is closed: contacts 99 and 94, winding I on relay P20, the parallel circuits over contacts 54l4 and 82-8i, selecting magnet Sal, contact 5!, selecting magnet S50, contacts 33 and 42, selecting magnet SM, contacts liJl, H0 and 20, wire h, contacts 26! and 4H, resistance TI to VI. Winding I on relay P20 has a low resistance, wherefore the selecting magnets SBI, S50 and S4! attract their armatures. The contacts 8H), 5H and 4H} are closed.

When relay P26 attracts its armature the selecting magnets B8i-B32 are connected to the test relays R3BR39, whereby the following parallel circuits are closed: contacts 483-465 in Fig. 4, windings on relays BSD-R39, wires u-v, contacts 28--3i, ill-92, 83-13, operating magnets BBL-Bill, to negative. Said windings on relays R30R39 have such a high resistance that the operating magnets B8lB82 have not yet been operated.

All the operating magnets in the cross-bar switches KIKB are held during a call over one of the multiple contacts which are closed, when the operating magnet attracts its armature. This is indicated in Figs. 1-2 by a connection between each operating magnet and the thick line which, in the symbol for a cross-bar switch, represents the multiple field of the operating magnet. When one of the operating magnets Ell-B12 and B8|B82 is busy, is connected to the winding of the operating magnet, wherefore none of the relays R30-R39, which at testing are connected to a busy operating magnet, can beoperated. Those of relays R30--R39, which are connected to a free operating magnet, on the other hand, operate. We suppose that at least relay R39 attracts its armature. The contacts 39i393 are operated. Relay R40 releases its armature and the contacts 403-405, disconnect the operating circuits for relays R30--R39, all of which, except R39, release their armatures. Relay R39 is held over contact 392. During the operating time for relay R39 and the release time for relay R40, the selecting magnets S85, S50 and S4! have completed their operation, and the corresponding operating magnets B59, B52, and BH now simultanecusly attract in the following circuits: contact 49!, wires m and t, contacts H and 21, 4H], 5% and 359, operating magnets BII, B42, and B51, to negative. Simultaneously, operating magnet B'H is also operated in the following circuit: contact 40!, contact 39!, wire 1), contacts 3d, 92 and 13, operating magnet B8l, to negative.

The operating magnets BBI, B5! and B62 and Eli are held over their own contacts in series with one of the wires a-c in Fig. 1. Such a switching process thereby takes place in the line equipment LR, that the register REG and the marker are released. A communication is thereafter connected between the line L and the line TI in Fig. 2 over the operating magnets Bl i, B42, B5! and BBI.

If relay VI in Fig. 1 does not connect any free path to the marker, relay V2 will connect a number of new circuits corresponding to the operating magnets B3IB4l instead of the operating magnets B32--B42 in the above description. Thus, it is achieved, that all the possible connecting paths through the selecting unit in Fig. 1 are tested and when one of the test relays RZEIR29 in Fig. 4 operates, a free path is didirectly selected through said selecting unit, which can reach at least one line within the called group of lines. The choice of connection path through the selecting unit in Fig. 2 is then effected similarly to the description above.

I claim:

1. In an automatic telephone system, a first selecting unit, a second selecting unit, each of said selecting units comprising primary and secondary cross bar switches connected by links, a calling line connected to a primary cross bar switch in the first selecting unit, a called group of lines connected to the secondary cross bar switch in the second selecting unit, a marking relay for said called group of lines for marking links in said selecting unit connectable to idle lines in said group, at least two groups of trunks each comprising a single trunk from each secondary cross bar switch in the first selecting unitfor connecting the secondary cross bar switches in said first selecting unit to the primary cross bar switches in said second selecting unit, a test circuit including a test conductor and a make contact for each of said trunks, an operating relay for said make contacts for each of said groups of trunks, a register, means connecting the calling line to the register and setting the latter in accordance with the telephone number designating the called group of lines, a marker including registering means, operating means and testing means, a marker selector connecting said register to said marker and through which the register transmits signals to the marker for designating the first selecting unit and said called group of lines for setting said registering means in accordance with said signals, a plurality of test conductors extending from said testing means in the marker, operating conductors extending from said operating means in the marker, and a marking conductor extending from said registering means in the marker, connecting means operated by said registering means connecting said test conductors to said links in said first selecting unit, said operating conductors to said operating relays, and said marking conductors to said marking relay, whereby said registering means actuates said marking relay and starts said operating means which selectively actuates said operating relays one at a time, and whereby said testing means stops said operating means upon closure of said make contacts for a group of trunks containing at least one idle trunk over which said called line can be connected to a line within said called group of lines. 2. In an automatic telephone system, a first selecting unit, a second selecting unit, each of said selecting units comprising primary and secondary cross bar switches connected by links, a calling line connected to a primary cross bar switch in the first selecting unit, a called group of lines connected to the secondary cross bar switch in the second selecting unit, a marking relay for said called group of lines for marking links in said selecting unit connectable to idle lines in said group, at least two groups of trunks each comprising a single trunk from each secondary cross bar switch in the first selecting unit for connecting the secondary cross bar switches in said first selecting unit to the primary cross bar switches in said second selecting unit, a test circuit including a test conductor and a make contact for each of said trunks, a register, an operating relay for said make contacts for each of said groups of trunks, means connecting the calling line to the register and setting the latter in accordance with the telephone number designating the called group of lines, a marker including registering means, operating means, and testing means, a marker selector connecting said register to said marker and through which the register transmits signals to the marker for designating the first selecting unit and said called group of lines for setting said registering means in accordance with said signals, a plurality of test conductors extending from said testing means in the marker, operating conductors extending from said operating means in the marker, and a marking conductor extending from said registering means in the marker, connecting means operated by said registering means for connecting said test conductors to said links in said first selecting unit, said operating conductors to said operating relays, and said marking conductor to said marking relay, whereby said registering means actuates said marking relay and starts said operating means which selectively actuates said operating relays one at a time, and whereby said testing means selects an idle link in said first selecting unit and a corresponding idle trunk over which said called line can be connected to a line within said called group of lines and stops said operating means in the position where said make contact for said selected trunk is closed.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,034,883 Scudder Mar. 24, 1936 2,363,955 Gillings Nov. 28, 1944 

